1. Maintain clean , deliverable lists.
If you start hammering some "20 MILLION EMAILS CD" list you bought from ebay, you will make nothing, you will get RBL'd , you will fail horribly. If you have a site with decent traffic, use that traffic to build an opt-in list . Offer a newsletter that pertains to your site. Don't spam it! Let it build up, keep the offers relevant to the site. After it's grown then send out one offer a week or so. If you don't have a site with decent traffic or a way to grow an optin list , come up with one. Most lists available for purchase are crap, have been spammed to shit and are more than likely full of spamtraps.
2. Remove unsubscribes / bounces.
This is obvious. If you keep mailing bounces, your IPs will be seen as spam sending bullshit and the providers will flag your mail. Not removing people that ask for it will only cause more complaints which will get your message / IP flagged. Especially with yahoo/aol/gmail/hotmail.
3. Don't send spammy crap: pills, porn, make money bullshit
Yeah, this should go without saying.
4. valid reverse dns on all ips you mail from
Most major providers will not accept mail from IPs without rdns..
5. DKIM/SPF settings on the mail from domains help delivery with larger providers.
Credibility , shows that the mail is coming from the right server. This helps with larger providers in lowering your 'spammy' score.
6. Maintain clean, deliverable lists.
Yeah, it's important.
7. If you're going to use email marketing for CPA offers, come up with your own creative and have them approve it. Using the CPA advertisers email ad-copy will raise spam flags. If they use images, modify the image to change the footprint. There are plenty of lazy CPA affiliates that just blast to their crappy lists with the same AD Copy you use. Any decent filtering system will learn from complaints by the end users and rank those as higher spam probability .
8. Use Spamassassin to check your message's "Spam score". While not 100% , it is a good general guide to use. It may raise flags on things you didn't consider would cause problems.